UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS. 


COLLEGE  OF  AGRICULTURE. 


AGRICULTURAL  EXPERIMENT  STATION. 


OBSERVATIONS  ON  SOME  VINE  DISEASES 
IN  SONOMA  COUNTY,  CALIFORNIA. 


By  O.  BUTLER. 


BULLETIN    No.    168 

(Berkeley,  Cal.,  May,  1905.) 


SACRAMENTO: 

:        :       SUPERINTENDENT    OF    STATE    PRINTING. 
1905. 


BENJAMIN  IDE  WHEELER,  Ph.D.,  LL.D.,  President  of  the  University. 

EXPERIMENT  STATION  STAFF. 

E.  W.  HILGARD,  Ph.D.,  LL.D.,  Director  and  Chemist. 

E.  J.  WICKSON,  M.A.,  Horticulturist. 

W.  A.  SETCHELL,  Ph.D.,  Botanist. 

ELWOOD  MEAD,  M.S.,  C.E.,  Irrigation  Engineer. 

C.  W.  WOODWORTH,  M.S.,  Entomologist 

R.  H.  LOUGHRIDGE,  Ph.D.,  Agricultural  Geologist  and  Soil  Physicist.    (Soils  and  Alkali.) 

M.  E.  JAFFA,  M.S.,  Assistant  Chemist.    (Foods,  Nutrition.) 

G.  W.  SHAW,  M.A.,  Ph.D.,  Assistant  Chemist.    (Starches,  Oils,  Beet-Sugar.) 

GEORGE  E.  COLBY,  M.S.,  Assistant  Chemist.    (Fruits,  Waters,  Insecticides.) 

RALPH  E.  SMITH,  B.S.,  Plant  Pathologist. 

A.  R.  WARD,  B.S.A.,  D.V.M.,  Veterinarian,  Bacteriologist. 

E.  W.  MAJOR,  B.Agr.,  Animal  Industry. 

A.  V.  STUBENRAUCH,  M.S.,  Assistant  Horticulturist,  in  charge  of  Substations. 

E.  H.  TWIGHT,  B.Sc,  Diplomd  E.A.M.,    Viticulturist. 

F.  T.  BIOLETTI,  M.S.,    Viticulturist. 

WARREN  T.  CLARKE,  B.S.,  Assistant  Field  Entomologist. 

H.  M.  HALL,  M.S.,  Assistant  Botanist. 

H.  J.  QUAYLE,  A.B.,  Assistant  Entomologist. 

GEORGE  ROBERTS,  M.S.,  Assistant  Chemist,  in  charge  Fertilizer  Control. 

C.  M.  HARING,  D.V.M.,  Assistant  Veterinarian  and  Bacteriologist. 

C.  A.  COLMORE,  B.S.,  Clerk  to  the  Director. 


R.  E.  MANSELL,  Foreman  of  Central  Station  Grounds. 
JOHN  TUOHY,  Patron, 


.    Tulare  Substation,  Tulare. 
JULIUS  FORRER,  Foreman, 

J.  E.  McCOMAS,  Patron,  Pomona,  -n 

J.  W.  MILLS,  Superintendent,  Pomona,  I 

y    Southern  California  Substation. 
In  charge  Cooperation  Experiments  of  Southern  California, 

JOHN  H.  BARBER,  Assistant  Superintendent,  Ontario, 

J.  W.  ROPER,  Patron, 

HENRY  WIGHTMAN,  In  charg 

ROY  JONES,  Patron,        ) 

„  >•   University  Forestry  Station,  Santa  Monica. 

WM.  SHUTT,  Foreman,    ) 

H.  O.  WOODWORTH,  M.S.,  Foreman  of  Poultry  Station,  Petaluma. 


[  University  Forestry  Station,  Chico. 
e,     ) 


The  Station  publications  (Reports  and  Bulletins),  so  long  as  avail- 
able, will  be  sent  to  any  citizen  of  the  State  on  application. 


CONTENTS 


Page. 

THE  RED-LEAF  DISEASE 5 

Description  of  the  Disease  and  Its  Relationships 6 

Effect  of  the  disease  on  the  leaves 6 

Effect  of  the  disease  on  the  fruit 8 

Effect  of  the  disease  on  the  shoots .   9 

The  relationships  of  the  Red-leaf  disease 9 

Resemblance  between  the  Red-leaf  disease  and  the  Folletage__ 9 

Resemblance  between  the  Rougeot  and  the  Red-leaf  disease 10 

Resemblance    between   the   Red-leaf  disease  and  the  California  (or  Anaheim) 

vine  disease 10 

Results  of  Winter  and  Summer  Spraying  Experiments 11 

Details  of  the  work  at  the  South  Sonoma  Experiment  Plot 13 

THE  GRAPE-SHRIVEL 18 

Description . _. 18 

Effect  of  the  disease  on  the  grapes 18 

Effect  of  the  disease  on  the  leaves 19 

Internal  appearance  of  the  shoots,  spurs,  arms,  and  body  of  vines 20 

Generalities  regardingthe  work  at  the  East  Sonoma  Experiment  Plot 21 

Cause  of  the  Grape-Shrivel 23 

ROOT-ROT 24 


OBSERVATIONS  ON  SOME  VINE  DISEASES  IN  SONOMA 
COUNTY,  CALIFORNIA. 

By  0.  BUTLER. 


Introduction. — In  1903  the  Viticultural  Department  of  the  College  of  Agriculture  of  the 
University  of  California  took  up  the  study  of  a  disease  that,  for  a  few  seasons,  had  been 
observed  in  Sonoma  County  and  was  beginning  to  cause  some  anxiety  among  the  vine- 
yardists.  After  an  inspection  of  the  vineyards  of  Sonoma  County  from  Santa  Rosa  to 
Cloverdale,  including  those  of  Alexander  Valley  and  Dry  Creek,  we  found  that  the 
"Red-leaf  disease,"  as  the  malady  was  called,  was  sufficiently  widespread  to  require 
special  attention.  The  "Red-leaf  disease"  was,  at  that  time,  associated  by  many  per- 
sons with  the  Anaheim  disease,  and  by  some  with  Anthracnose.  The  first  theory  was 
set  aside  a  priori,  on  account  of  the  difference  in  the  effect  on  the  canes  and  grapes,  and 
also  on  account  of  the  lack  of  virulence  of  the  disease  when  attacking  the  Mission  vines.* 
The  suggestion  that  it  might  be  Anthracnose  was  easily  set  aside,  as  the  markings  of 
the  disease  on  leaves,  canes,  and  berries  are  of  an  entirely  different  character ;  it  is  very 
doubtful  that  the  true  Anthracnoset  has  ever  been  found  in  a  vineyard  of  California. 

On  my  return  from  this  trip  of  investigation,  I  passed  through  Napa  Valley  to  com- 
pare the  "  Red-leaf  disease  "  with  a  malady  of  similar  character  that  had  caused  damage 
in  some  sections,  and,  after  a  consultation  with  Dr.  E.  W.  Hilgard,  it  was  decided  to 
start  a  methodic  study  of  the  "Red-leaf  disease,"  and  Mr.  O.  Butler  was  appointed  to 
carry  out  the  investigations.  This  bulletin  gives  the  results  of  his  preliminary  obser- 
vations. 

During  the  same  season  arrangements  were  made  with  several  vineyardists  to 
establish  experiment  plots  on  their  land  during  the  following  year. 

While  investigating  the  "  Red-leaf  disease,"  Mr.  Butler  found  that  a  number  of  mala- 
dies, either  parasitic  or  physiological,  were  responsible  in  a  measure  for  the  weakness  or 
dying  of  the  vines.  Among  these  affections  Phylloxera,  Root-rot,  Mildew,  lack  of  affinity 
between  scion  and  stock,  lack  of  adaptation  of  stock  to  soil,  mechanical  injuries,  Erinose, 
and  Black-knot  are  quite  prevalent  in  Sonoma  County,  as  well  as  in  most  vineyard 
districts  of  California. 

A  description  of  some  of  these  will  be  given  in  separate  bulletins,  while  others  have 
been  already  discussed  in  former  publications:  Report  of  Viticultural  Commission. 
1893;  Bulletins  Nos.  127,  131,  146,  148,  of  the  Agricultural  Experiment  Station  of  the 
University  of  California. X 

Mr.  Butler's  observations  seem  to  show  that  the  cause  of  the  Red-leaf  disease  is  not 
parasitic,  but  that  it  is  more  probably  due  to  soil  and  atmospheric  conditions.  These 
observations  will  be  kept  up  during  the  coming  season,  and  a  careful  examination  of  the 
subsoil  and  moisture-contents  of  the  experimental  plots  will  be  made  through  the  grow- 
ing season,  so  that  definite  conclusions  may  be  drawn. 

E.  H.  T WIGHT. 

THE  RED-LEAF  DISEASE. 

In  1903,  the  attention  of  the  public  was  aroused  by  the  alarming- 
notices  published  in  the  Sonoma  County  papers  about  a  new  and  mys- 
terious malady,  which  was  unanimously  denominated  Red-leaf  disease. 
Opinions  were  freely  aired   as  to  the  nature  of  the  disease,  but  the 

*N.  B.  Pierce,  Bulletin  No.  2,  Div.  Veg.  Path.,  U.  S.  Dept.  Agr.,  page  7. 
t  Sphaceloma  ampelinum. 

JAlso,  in  "American  Vines,"  by  P.  Viala  and  Ravaz ;  translated  from  the  French  by  R  Dubois 
and  E.  H.  Twight. 


6  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION. 

disease  itself  was  not  described.  The  reader  was  left  to  conjecture, 
from  the  name  the  grape-growers  were  agreed  upon  giving  to  it,  that  a 
red  leaf  was  its  main  characteristic.  Beyond  this,  however,  the  grape- 
growers  did  not  entirely  agree ;  the  term  red  leaf  is  indefinite  enough 
to  allow  of  a  wide  individualistic  interpretation,  and  the  grower  who 
had  vines  suffering,  or  dying,  from  a  cause  undiscoverable  to  him,  and 
showing  a  foliage  tinted,  perchance,  here  and  there  with  red,  was 
inclined  to  call  the  trouble  from  which  his  vines  were  suffering  the 
Red-leaf  disease.  This  diversity  of  opinion  was  at  first  rather  confusing, 
and  was  more  a  hindrance  than  a  help  in  furthering  the  investigations. 
In  fact,  of  the  three  vineyards  kept  constantly  under  observation,  only 
one  was  finally  found  to  be  free  from  any  other  disease  than  the  Red- 
leaf  ;  and  the  development  and  characteristics  of  the  said  disease  in 
this  vineyard  were  a  great  help  in  diagnosing  the  malady  in  other 
parts  of  the  county,  and  under  less  favorable  circumstances. 

The  result  of  our  investigations  of  the  disease  under  consideration 
may  be  conveniently  divided  into  two  parts  :  (1)  Description  of  the 
Red-leaf  disease  and  its  relationships  ;  and  (2)  Results  of  the  winter  and 
summer  spraying  experiments  instituted  to  combat  it. 

DESCRIPTION    OF    THE    DISEASE    AND    ITS    RELATIONSHIPS. 

The  Red-leaf  disease  may  affect  the  shoots,  the  leaves,  the  peduncles, 
the  pedicel,  and  the  fruit  of  the  vine;  it  may  affect  the  uppermost  part 
of  a  cane,  or  several  canes;  one  entire  side  of  a  vine,  or,  but  more 
rarely,  an  entire  vine.  One  vine  may  show  all  the  characteristics  of 
this  disease,  and  another  only  a  part,  or  perhaps,  only  one  of  them- 
The  disease  may  never  proceed  beyond  the  first  stages,  a  not  uncommon 
feature,  or  it  may  develop  slowly  until  all  its  characters  are  patent  to 
the  most  casual  observer;  more  often,  however,  its  development  is  rapid, 
and  it  would  be  somewhat  difficult  to  distinguish  the  first  stage,  which  is 
rather  obscure,  from  those  final  stages  which  characterize  it  particularly. 

Allowing,  then,  for  the  irregularities  in  the  development  of  the  Red- 
leaf  disease,  and  for  the  absence  of  anything  like  progression  from  one 
stage  to  another,  the  reader  will  find  in  the  following  description  the 
means  of  identifying  this  disease,  without  much  difficulty,  whenever  it 
occurs  in  his  vineyard. 

Effect  of  the  Disease  on  the  Leaves. — The  leaves  near  the  apex  of  the 
shoots,  including  those  recently  expanded,  and  perhaps  for  a  foot  or  two 
down,  become  pale,  especially  in  the  interveinar  spaces.  If  a  leaf  in  this 
stage  is  picked  and  observed  by  transmitted  light,  and  with  the  under- 
side facing  the  eye,  all  the  fine  network  of  veins  will  be  found  to  be 
discolored.  This  discoloration  of  the  small  veins  appears  simultane- 
ously  with   the   Joss  of  color  in   the   leaves;  in   the  recently  expanded 


OBSERVATIONS   ON   SOME   VINE   DISEASES   IN   SONOMA   COUNTY.  7 

leaves,  which  are  naturally  yellowish-green,  this  discoloration  is  more 
indicative  of  the  disease  than  the  change  in  color.  Following  the  loss  of 
color,  the  leaves  become  somewhat  convex  and  the  edges  curl  toward 
the  lower  surface;  they  lose  their  natural  appearance;  the  tissue 
between  the  main  veins  sinks,  and  the  veins  themselves  stand  out  like 
ribs.  In  mild  cases  the  disease  may  develop  no  further  than  this.  The 
affected  leaves,  however,  fall  off  sooner  or  later,  and  generally  with 
their  stalks  (petioles). 

In  severe  cases  of  the  disease,  the  recently  expanded  leaves  may  dry 
up  suddenly  and  totally  without  malformation  of  any  kind;  or,  as 
occurs  more  frequently,  the  parenchyma  becomes  pale  yellowish-green, 
and  the  inclosed  network  of  small  veins  discolored;  then,  usually,  the 
lobe,  or  at  least  the  upper  portion  of  it,  or  in  entire  leaves  that  portion 
of  the  parenchyma  which  occupies  the  equivalent  position,  including 
one  wing  of  the  petiolary  sinus,  becomes  more  or  less  convex  and  the 
tissue  sunken  between  the  veins,  which  stand  out,  often  in  bold  relief. 

At  this  stage  the  tissues  begin  to  dry  rapidly  from  the  periphery  toward  the  petiole, 
at  the  same  time  retaining  their  peculiarity  of  form.  When  dry,  the  tissues  are  brittle 
and  reddish  brown.  As  soon  as  the  discoloration  has  reached  the  petiole,  the  entire 
leaf  and  leaf-stalk  may  fall  together.  In  older  leaves,  those  not  yet  fully  developed  and 
still  growing,  one  observes  great  variations— variations  which  can  not  be  accounted  for 
by  the  position  of  the  leaf  in  relation  to  other  diseased  leaves,  or  by  its  age.  Some  leaves 
show  the  characteristics  just  described  as  typical  of  recently  expanded  ones,  except 
that  they  do  not  fall  prior  to  the  dying  of  the  convex  and  furrowed  area.  The  drying 
of  that  portion  of  the  leaf  proceeds  as  rapidly  in  one  case  as  in  the  other.  In  the  more 
fully  developed  leaves,  however,  the  action  is  sufficiently  striking.  At  the  petiole,  and 
in  the  region  immediately  adjoining  it,  the  mid-rib  serves  as  a  line  of  demarkation 
between  the  living  and  the  dead  tissues.  The  dead  tissue  soon  separates  from  the 
petiole,  which,  in  turn,  discolors.  At  this  stage  the  leaf-blade  separates  from  the  petiole, 
which,  though  drying  up  and  discoloring  more  or  less  from  the  apex  down,  remains  a 
while  longer  attached  to  the  shoot,  In  other  cases,  besides  the  dead  and  furrowed  area, 
there  may  appear  between  the  veins,  on  other  parts  of  the  leaf,  spots  which,  at  first  yel- 
lowish, become,  at  the  same  time  as  the  aforementioned  area,  dry  and  reddish-brown 
in  color,  except  for  a  narrow  margin  next  to  the  still  green  or  greenish-yellow  tissue. 
Or  again,  the  leaves  may  present  the  following  appearance :  The  leaf-tissue,  while  still 
green,  becomes  sunken  between  the  veins;  then,  in  one  or  sometimes  both  corners,  the 
leaf  becomes  pale  greenish-yellow  and  between  the  veins,  in  the  remainder  of  the  leaf, 
appear  spots  of  various  sizes  of  the  same  color.  These  spots  enlarge  and  even  run 
together  to  form  stripes.  At  this  stage  the  discolored  areas  begin  to  dry  rapidly,  assum- 
ing the  familiar  reddish-brown  color.  The  tissues  next  the  petiolary  sinus  rapidly  dry 
up  from  the  periphery  inwards,  but  do  not  encroach  upon  the  mid-rib,  and  one  may 
sometimes  find  a  leaf  which  still  adheres  to  its  stalk,  after  the  parenchyma  on  each 
side  has  become  detached.  A  slight  margin  of  yellowish-green  sometimes  separates  the 
dead  furrowed  area  from  the  still  living  tissues;  this  margin  of  yellow  is,  however, 
generally  more  distinct  around  the  spots  and  stripes  of  dead  tissue  in  the  other  parts  of 
the  parenchyma.    The  leaves  fall  from  the  petioles,  which  soon  follow  them. 

In  fully-developed  leaves  and  old  leaves,  the  disease  is  not  accom- 
panied by  any  distortion  or  furrowing  of  the  leaf-blade.  It  affects  only 
the  tissues  between  the  main  veins,  and  first  appears  as  suffused  green- 
ish-yellow spots,  which,  at  first  indefinite,  become  gradually  larger  and 
more  definite  in  outline,  and  often  merge  together,  forming  large  macu- 


8  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION. 

lations  and  stripes,  which  are  more  or  less  yellow — the  intensity  of  the 
colorations  depending,  it  would  seem,  on  the  rapidity  with  which  the 
disease  has  progressed.  The  center  of  the  spot  now  dies,  becoming 
reddish-brown,  sometimes  almost  with  a  brick  tint  and  a  sub-glossy 
appearance  when  death  has  been  rapid.  According  to  the  rapidity  of 
death  these  spots  or  stripes  are  surrounded,  either  (a)  with  a  thin 
border  of  dull,  deep  red,  which,  in  turn,  is  separated  by  a  suffused 
yellow  or  greenish-yellow  band  from  the  green  of  the  still  healthy  sur- 
rounding tissues;  or  (h)  with  a  border  of  yellow,  either  suffused  and 
broad,  or  thin  and  with  a  more  definite  margin;  or  (c)  directly  by 
the  healthy  green  tissue  itself.  Sometimes  the  old  leaves  near  the  base 
of  the  shoots  show  a  slight  variation  from  the  characteristics  just 
described.  These  leaves,  as  soon  as  the  disease  begins  to  appear  between 
the  veins  and  the  spots  enlarge  and  merge  to  form  stripes,  become  more 
or  less  greenish-yellow  in  the  entire  parenchyma.  The  dead  areas, 
instead  of  being  reddish-brown  and  in  sharp  contrast  to  the  living 
tissues,  are  fawn-colored  and  soft,  crumbly,  tear  easily,  and  fall  away. 
The  affected  leaves  thus  become  deeply  incised,  sometimes  almost  to  the 
petiole,  from  which  they  hang  in  two,  three  or  more  pieces. 

In  the  case  just  described,  as  likewise  in  the  preceding,  the  leaves 
may  remain  attached  to  the  shoots  for  an  indefinite  time,  and  when 
they  fall  it  may  be  either  with  the  petioles,  or  before  them. 

Effect  of  the  Disease  on  the  Fruit. — The  fruit  of  white  varieties  of 
grapes  appears  to  be  more  sensitive  to  the  Red-leaf  disease  than  that 
of  black  varieties.  It  would  seem  that  the  latter  show  the  character- 
istics of  this  disease  more  markedly  on  the  foliage,  except  in  severe 
cases,  and  toward  autumn,  whereas  in  the  former  the  disease  is  more 
conspicuous  on  the  berries. 

The  Red-leaf  disease  may  affect  the  fruit  soon  after  setting.  When 
this  occurs,  on  passing  the  hand  over  a  diseased  bunch  of  grapes,  the 
berries  come  off  either  with  or  without  the  pedicels.  They  even  fall  of 
themselves,  and  the  stem  (peduncle)  dries  up  and  falls  also.  This 
manifestation  of  the  disease  is  more  frequent  among  the  red  than  the 
white  grapes.  The  more  noteworthy  characters  begin  to  show  unmis- 
takably on  the  berries  when  the  clusters  of  grapes  are  a  month  or  a 
month  and  a  half  old,  and  only  become  general  just  prior  to  the  begin- 
ning of  maturation.  The  berries  become  suffused  with  livid  discolora- 
tions,  which  are  sub-cuticular,  the  cuticle  itself  not  being  affected  until 
later.  The  tissue  of  the  berries  in  the  center  of  these  spots  generally 
falls  away  from  the  epidermis,  which  then  collapses.  The  livid  and 
sunken  spots  thus  formed  may  be  more  or  less  numerous,  and  large  or 
small;  they  are  more  frequent  on  the  exposed  berries  than  on  those  in 
constant  shade;  they  are  more  frequent  on  the  sides  of  the  berries 
exposed  to  the  light  than  on  the  shady  sides.  When  they  do  not  fall 
off  at  this  stage,  the  berries  shrivel  and  dry  up. 


OBSERVATIONS    ON    SOME    VINE   DISEASES   IN    SONOMA    COUNTY.  H 

When  the  berries  become  affected  just  previous  to  maturity,  or  after 
maturity  has  begun,  they  ripen  imperfectly  and,  as  a  rule,  are  never 
worth  picking.  The  clusters  of  diseased  grapes  are  generally  allowed 
to  remain  on  the  vine,  and,  after  defoliation,  they  may  be  observed 
hanging  from  the  canes. 

Effect  of  the  Disease  on  the  Shoots. — The  shoots  are  not  affected  directly 
by  the  Red-leaf  disease.  The  symptoms  they  show  are  a  consequence, 
so  to  speak,  of  the  intensity  of  the  malady  on  the  leaves.  When  the 
shoots  are  partially  defoliated  (counting  from  the  apex),  their  growth 
is  only  checked  for  a  while.  When  the  defoliation  is  more  severe,  the 
apex  curls  somewhat,  discolors  and  dies.  Death,  however,  is  not  con- 
fined to  the  apex,  but  proceeds  for  a  greater  or  less  distance  down  the 
shoots,  the  discoloration  progressing,  as  it  were,  by  stages.  The  shoots 
shrink  and  gradually  turn  brown.  The  shrinkage  of  the  tissues  is  most 
noticeable  near  the  nodes,  and,  except  in  more  lignified  parts  of  the 
shoots,  always  precedes  the  discoloration.  The  discoloration  of  the 
shoots  is  somewhat  irregular,  and  more  rapid  in  the  parts  exposed  to 
the  sun.  When  defoliation  is  complete,  the  shoots  sometimes  die  from 
apex  to  base.  When  they  are  not  defoliated,  their  lignification  does 
not  seem  to  be  materially  interfered  with,  though  it  is  often  irregular. 
One  may  even  find,  in  rare  cases,  green  immature  spots  or  stripes  in 
the  midst  of  lignified  tissue,  but  even  such  an  irregularity  as  this  does 
not  persist.     The  immature  spots  mature  in  time. 

The  Relationships  of  the  Red-leaf  Disease. — The  Red-leaf  disease 
appears  more  or  less  closely  related  to  the  Folletage,  the  Rougeot,  and 
the  California  Vine  disease.  It  resembles  the  Folletage  by  the  sporadic 
suddenness  with  which  it  sometimes  appears;  the  Rougeot,  in  its  not 
being  immediately  fatal,  and  possibly  also  in  some  of  its  foliar  colora- 
tions; and  the  California  (Anaheim)  vine  disease  in  the  striping  of  the 
leaves. 

The  cause  of  the  Folletage  and  of  the  Rougeot  has  been  thought  to  be 
due  to  the  rupture  of  equilibrium  between  transpiration  and  absorption, 
but  that  of  the  California  vine  disease  has  not  been  determined.  In 
the  case  of  the  Red-leaf  disease,  the  evidence  gathered  in  a  single  season 
seems  to  point  to  a  physical  rather  than  to  a  parasitic  cause. 

Resemblance  between  the  Red-leaf  Disease  and  the  Folletage. — The 
Folletage  affects  the  vines  in  midsummer.  "  One*  sometimes  observes, 
especially  in  July  and  August,  vines  in  excellent  health  dying  suddenly 
in  a  vineyard.  The  leaves  wilt,  fade,  and  dry;  the  shoots  and  even  the 
arms  succumb.  The  vines  may  die  in  a  few  minutes.  *  *  *  It  is 
only  isolated  vines  (they  may  sometimes  be  numerous)  which  are 
affected  by  this  disease;  *  *  *  a  whole  vineyard  is  never  affected. 
Entire  shoots,  or  even  whole  arms,  may  be  destroyed  on  a  diseased  vine 

*P.  Viala:  "  Les  Maladies  de  la  Vigne,"  page  471. 


10 


UNIVERSITY    OF   CALIFORNIA — EXPERIMENT   STATION. 


without  the  other  arms  or  shoots  being  affected."  Vines  planted  in 
"deep,  cool,  damp  soils"  are  subject  to  this  trouble,  especially  when 
heat  follows  heavy  rains.  In  dry  soils  the  Folletage  also  occurs.  In 
both  cases  it  is  due  to  a  rupture  of  the  equilibrium  between  the  trans- 
piration of  the  leaves  and  the  absorption  of  the  roots.  The  resemblance 
between  the  effect  of  the  Folletage  and  that  of  the  Red-leaf  disease  is 
not  a  very  close  one.  The  Red-leaf  disease  is  apparently  not  fatal  in  a 
single  season,  if  ever.  Like  the  Folletage,  however,  it  affects  the  vines 
with  greatest  intensity  and  suddenness  during  July  and  August,  and 
more  frequently  partially  than  wholly.  The  death,  either  total  or 
partial,  of  the  affected  shoots  does  not  follow  the  attack  in  the  great 
majority  of  cases.  In  some  cases  of  Folletage,  the  foliar  characteristics 
are  very  similar  to  those  of  vines  affected  with  the  Red-leaf  disease,  if 
we  may  judge  from  plates  17,  18,  and  19  given  as  illustrations  of  this 
disease  in  Bulletin  No.  2  of  the  Division  of  Vegetable  Pathology,  U.  S. 
Department  of  Agriculture. 

Resemblance  between  the  Rougeot  and  the  Red-leaf  Disease. — The  Rou- 
geot  is  considered  by  some  authors  as  a  mild  form,  so  to  speak,  of  the 
Folletage,  and  attributable  to  the  same  cause.  The  Rougeot  affects 
vines  as  sporadically  and  irregularly  as  the  Red-leaf  disease.  Its  foliar 
characteristics  remind  one  of  those  of  the  Anaheim,  or  the  Red-leaf 
disease.     Vines  affected  with  Rougeot  generally  recover. 

Resemblance  between  the  Red-leaf  and  the  California  (or  Anaheim) 
Vine  Disease. — For  a  description  of  this  disease  the  reader  is  referred 
to  Pierce's  memoir  on  the  subject.*  To  describe  the  disease,  even  in 
the  most  summary  manner,  is  not  necessary  in  the  present  publication. 
The  California  vine  disease  and  the  Red-leaf  disease  are  sufficiently 
different  from  each  other,  in  their  salient  characteristics,  to  be  easily 
distinguished  without  resorting  to  details.  The  reader  will  find,  in  the 
following  comparison,  a  sufficient  proof  of  the  distinctiveness  of  these 
two  diseases: 


Anaheim  Disease,  t 

The  disease  is  cumulative. 

The  newly-formed  leaf  either  remains 
green  or  is  striped  yellow  or  red,  accord- 
ing as  the  grapes  are  white  or  red.  (loc. 
tit.,  page  142.) 

As  a  rule  the  leaves  fall  from  the  base  of 
the  canes  first,    (loc.  cit.,  page  45.) 

The  roots  are  decayed,  (loc.  cit.,  page  57, 
e1  suiv.) 

Grapes  dry  and  remain  on  the  vine,  or  fall 
off,  hut  not  very  frequently,  (loc.  cit., 
page  53.) 
\  diseased  vine  shows  the  disease  most 
generally  on  all  its  shoots,  {loc.  cit., 
page  79.) 

'  Boll.  No.  2,  Div.  Veg.  Path.,  U.  S.  Dept. 
•  \.  P>.  Pierce:    -California  Vine  Disease, 


Bed-leaf  Disease. 

The  disease  is  not  cumulative. 

The  newly-formed  leaves  either  dry  with 
deformation  (leaves  j  ust  expanded )  or  are 
paler  than  normally  and  convex  (leaves 
two  or  more  nodes  from  the  apex). 

The  leaves  fall  from  the  apex  first. 

The  roots  are  healthy. 

Grapes  are  mottled  with  livid,  sunken 
spots. 

The  number  of  shoots  affected  is  variable, 
though  rarely  total. 


Agr. 
'  loc, 


cit. 


OBSERVATIONS    ON    SOME    VINE    DISEASES   IN    SONOMA    COUNTY. 


11 


The  above  consideration  of  the  relations  of  the  Red-leaf  disease  leads 
one  to  conclude  that  the  Red-leaf  and  the  Rougeot  are  the  more  closely 
related.  If  this  conclusion  is  proved  to  be  correct,  then  the  grower 
need  not  feel  greatly  alarmed  even  when  a  considerable  percentage  of 
his  vines  are  affected  with  the  Red-leaf  disease. 

RESULTS    OF    WINTER    AND    SUMMER  SPRAYING    EXPERIMENTS. 

Toward  the  end  of  January,  1904,  the  active  help  of  three  growers, 
who  were  anxious  to  find  a  remedy  for  the  Red-leaf  disease,  was 
obtained.  The  vineyards  of  these  growers  are  situated  respectively  in 
the  south,  in  the  north,  and  in  the  east  of  Sonoma  County. 

Those  portions  of  their  vineyards  supposed  to  be  most  affected  with 
this  disease  were  selected  for  experimental  purposes.  It  had  been  our 
intention  to  divide  the  plots  off  and  to  spray  them  after  the  manner 
shown  in  the  following  diagram,  but  owing  to  inclement  weather  the 
spraying  with  the  iron  sulfate  was  not  completely  carried  out,  except 
at  the  East  Sonoma  experiment  plot. 


1.    Arrangement  of  Experiment  Plots. 


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The  North  Sonoma    experiment  plot  was  not  sprayed  with  the  iron 
sulfate  at  all,  and  the  diagram  of  the  plot  as  sprayed  would  be: 


Bordeaux  mixture 


Witness 


Bordeaux  mixture 
Witness 


Bordeaux  mixture 


12 


UNIVERSITY    OF    CALIFORNIA  — EXPERIMENT    STATION. 


The  sprays  used,*  the  dates  of  their  application,  the  amount  of  each 
used  per  acre,  and  the  length  of  the  vine  shoots  when  they  were  applied, 
are  given  in  the  following  tables.  From  these  tables  the  cost  of  the 
spraying,  exclusive  of  the  labor,  may  be  approximately  determined: 

Amount  of  spray  used  on  fair  vines  of  the  Burger  variety;  1210  vines  per  acre. 


Date. 


Acid  Iron 
Sulfate. 


Bordeaux 
Mixture. 


Average  Length 
of  Canes. 


May  3  and  4 

May  23 

June  7 

July  19 


Was  unable  to 
use  this  spray 
on  account  of 
bad  weather. 


70  gallons 

85  gallons 

100  gallons 

140  gallons 


9  inches 
30  inches 
36  inches 
3.5-4  feet 


On  the  South  Sonoma  experiment  plot  half  of  the  intended  sprayinj 
with  the  iron  sulfate  was  carried  out. 

Amount  of  spray  used  on  old,  large  vines  of  the  Mission  variety;  680  vines  per  acre. 


Date. 


Acid  Iron 
Sulfate. 


Bordeaux 
Mixture. 


Average  Length 
of  Cane. 


February  2 400  gallons 

April  28 !  none 


May  13 

June  14  and  15. 

July  18 


none 
none 
none 


none  0 

80  gallons  9  inches 

105  gallons  20  inches 

270  gallons  3.5-5  feet 

530  gallons  4-6  feet 


The  growth  of  the  vines  at  the  East  Sonoma  experiment  plot  was  too 
uneven  to  be  of  value  for  tabulation. 

The  three  experiment  plots  very  soon  proved  to  be  of  very  unequal 
value  for  the  study  of  the  Red-leaf  disease.  The  vines  in  the  East 
Sonoma  plot  were  practically  not  affected  by  this  disease,  though  seri- 
ously menaced  by  one  which  will  be  described  below  under  the  name  of 
Grape-shrivel.  The  Red-leaf  disease  was  prevalent  in  the  North  Sonoma 
plot,  but  so  also  was  the  Root-rot.  At  the  South  Sonoma  plot,  however, 
the  vines  were  not  affected  with  any  other  disease  than  the  Red-leaf, 
and  it  is  there  that  practically  all  the  data  on  the  development  and 
progress  of  this  malady  were  gathered.     Notwithstanding  the  presence 

*The  sprays  used  were:  1.25  per  cent  Bordeaux  mixture,  and  acid  iron  sulfate.  The 
acid  iron  sulfate  is  prepared  as  follows:  Ten  pounds  of  iron  sulfate  are  placed  in  a  half- 
barrel,  one  pound  of  commercial  sulfuric  acid  is  poured  into  the  copperas  (to  prevent 
sputtering,  which  is  objectionable,  the  acid  should  always  be  added  before  the  water), 
then  12.5  gallons  of  water  are  added  and  the  mass  stirred  until  the  sulfate  has  dissolved. 
In  making  large  quantities  of  the  acid  iron  sulfate  spray  it  is  more  expeditious  to  use 
hoi  water.  The  iron  sulfate  is  only  a  winter  spray,  and  can  not  be  used  after  the  buds 
have  swollen. 


OBSERVATIONS   ON    SOME   VINE   DISEASES   IN   SONOMA    COUNTY. 


13 


of  other  diseases,  the  North  Sonoma  plot,  and  a  few  side  excursions  to 
other  vineyards,  were,  however,  of  valuable  assistance  as  soon  as  some 
knowledge  of  the  characteristics  of  the  Red-leaf  disease  had  been 
obtained.  By  their  aid  the  limits  of  variability  of  these  characteristics 
were  established  with  considerable  accuracy. 

In  the  following  discussion  of  the  effect  of  our  spraying  experiments 
in  controlling  the  Red-leaf  disease,  together  with  the  observations  on 
its  progress  and  development  in  the  vineyard,  the  data  collected  at  the 
South  Sonoma  experiment  plot  form  the  basis  of  our  discussion. 

Details  of  the  Work  at  the  South  Sonoma  Experiment  Plot. — The  plot 
was  established  among  old  Mission  vines  which  had  been  more  or  less 


Hay  "Field 

TErtCE 


Fig.  1.    Map  of  South  Sonoma  Experiment  Plot. 

diseased  in  1902  and  1903  and  were  beginning  to  cause  some  concern. 
By  referring  to  the  map  (Fig.  1)  the  reader  will  at  once  see  the  manner 
in  which  the  plot  was  laid  off  and  sprayed.  The  times  at  which  the 
sprayings  were  given  have  already  been  mentioned.  The  interval 
between  the  sprayings  with  the  Bordeaux  mixture  was  so  timed  as  to 
always  keep  the  leaves  well  covered  with  a  film  of  the  fungicide.  The 
Bordeaux  was  observed  to  cause  a  certain  amount  of  burning  in  the 
young  leaves,  especially  in  the  earlier  part  of  the  season.  This  burning 
of  the  tissues,  which  occurs  between  the  veins  and  in  stripes,  the  leaves 
becoming,  as  a  consequence,  somewhat  crinkled  and  distorted,  should 
not  be  confused  with  the  characteristics  of  the  Red-leaf  disease.     The 


14  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

vines  sprayed  with  the  acid  iron  sulfate  were  greener  than  the  wit- 
nesses, at  least  during  the  first  part  of  the  growing  season ;  the  vines 
sprayed  with  the  Bordeaux  mixture  were  much  greener  than  the  wit- 
nesses, even  in  the  height  of  summer.  This  improvement  in  the  color 
of  the  foliage,  where  and  whenever  the  above  fungicides  are  used,  occurs 
regardless  of  the  presence  or  absence  of  disease. 

The  Red-leaf  disease  first  appeared  in  the  plot  on  the  10th  of  June, 
when  a  single  vine  was  found  somewhat  affected.  On  the  10th  of  July 
there  was  hardly  more  than  one  per  cent  of  the  vines  affected.  From 
then  to  the  end  of  the  season,  however,  the  disease  rapidly  increased. 
On  the  25th  of  August  about  ten  per  cent  of  the  vines  were  affected, 
which  gives  an  increase  of  nine  per  cent  in  thirty-six  days.  From  the 
25th  of  August  to  the  13th  of  October,  the  increase  was  only  five  per 
cent. 

If,  instead  of  considering  the  plots  as  a  whole,  we  compare  the  percentages  of 
diseased  vines  among  the  sprayed  and  unsprayed  rows,  we  will  find  that  the  Red-leaf 
disease  develops  almost  as  freely  in  the  one  case  as  in  the  other,  with  one  exception. 
In  the  case  of  the  witnesses  (average  of  seven  sections)  the  disease  is  more  rapid  from 
the  10th  to  the  28th  of  July  than  in  the  case  of  the  sprayed  vines ;  but  between  July  28th 
and  August  25th  it  is  proportionately  less  rapid  than  among  the  vines  sprayed  with  the 
acid  iron  sulfate  and  not  much  greater  than  among  those  sprayed  with  the  Bordeaux 
mixture.  The  rapid  rise  in  the  percentage  of  diseased  vines  in  the  sprayed  rows  begins 
later  than  in  the  average  of  the  witnesses,  and  on  the  28th  of  July.  On  the  12th  of 
August  the  vines  sprayed  with  the  iron  sulfate  show  a  greater  percentage  of  diseased 
vines  than  the  witnesses,  and  throughout  the  remainder  of  the  season  continue  to  do  so. 
Among  the  vines  sprayed  with  the  Bordeaux  mixture  the  percentage  of  disease  remains 
below  that  of  the  witnesses,  except  on  the  13th  of  October,  when  it  is  almost  one  percent 
higher.  The  vines  sprayed  with  the  iron  sulfate  and  Bordeaux  mixture  (one  section) 
showed  1.6  per  cent  diseased  vines  all  through  July ;  between  July  28th  and  August  12th 
the  percentage  increased  to  5.4  per  cent,  and  from  that  date  until  October  13th  the 
number  of  diseased  vines  gradually  increased  until  it  reached  9.3  per  cent.    (See  Fig.  2.) 

The  distribution  of  the  diseased  vines  in  the  plot  is  quite  sporadic. 
The  disease  does  not  progress  from  any  one  center,  or  many  centers. 

In  the  map  (Fig.  1)  the  position  of  the  diseased  vines  on  October  13th 
is  marked  by  a  circle;  the  crosses  representing  the  vines.  The  reader 
will  at  once  notice  that  the  diseased  vines  are  very  scattered,  their 
grouping  very  indefinite,  and  he  would  be  unable  to  tell  from  the  map 
where  the  disease  first  started.  On  the  10th  of  June  there  was  one 
diseased  vine  in  sections  6,  8,  12.  On  the  map,  which  shows  the  posi- 
tion of  the  diseased  vines  on  October  13th,  there  is  not  the  remotest 
suggestion  of  four  centers  of  infection.  From  this  fact  we  may  conclude 
that  priority  of  infection  has  little  to  do  with  the  spread  of  the  Red-leaf 
disease.  And  this  is  the  more  especially  worthy  of  note  since  priority 
of  infection  is  generally  a  most  decided  factor  in  the  spread  of  parasitic 
diseases.  The  reader  has  only  to  recall  to  mind  the  action  of  the 
Phylloxera,  the  Root-rot,  the  Mildew,  etc.  The  parasite  causing  a  given 
disease  may  spread  from  one  plant  to  another  in  a  more  or  less  regular 


OBSERVATIONS    ON    SOME   VINE    DISEASES   IN    SONOMA    COUNTY. 


15 


manner,  which  depends  largely  on  the  nature  of  the  parasite  and  the 
surrounding  conditions.  If  the  parasite  lives  on  the  roots  of  the  plant, 
it  will  spread,  as  it  were,  in  a  circle;  but  if  it  is  a  leaf  parasite,  the  wind, 
all  other  things  being  equal,  will  cause  the  disease  to  spread  with  greater 
rapidity  in  the  direction  in  which  it  blows.  Furthermore,  when  a  plant 
is  preyed  upon  by  some  parasite,  it  shows  all  the  symptoms  character- 
istic of  the  specific  disease,  from  the  minor  to  the  major  in  sequence. 
Now  if  we  apply  these  principles  to  the  study  of  the  Red-leaf  disease, 

Legend:  Iron  sulfate  spray. 

Witnesses. 

—  —  ■  —  —  Bordeaux  mixture. 

Iron  sulfate  and  Bordeaux  mixture. 


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July. 

.August . 

September  . 

October . 

Fig.  2.    Progress  of  the  Red-leaf  disease  (in  per  cent)  on  the  South  Sonoma 
Experiment  Plot. 

we  find  that  it  does  not  spread  from  a  center  of  infection.  A  vine  is 
often  diseased  on  a  single  shoot;  it  may  show  the  first  symptoms  of 
disease  in  the  early  summer,  and  never  at  any  other  time.  Some 
healthy  vines  may  in  seven  days  be  affected  in  the  worst  form,  while 
others  have  only  a  cane  or  two,  or  even  only  the  apical  leaves  of  a  few 
shoots,  affected.  These  observations  tend  to  show  that  the  Red-leaf 
disease  is  not  caused  by  a  root  parasite. 

It  remains  to  be  seen  whether  or  not  the  Red-leaf  disease  can  be 
caused  by  a  leaf  parasite.  The  disease  progressed,  the  reader  will  remem- 
ber, from  section  2  toward  section  12  (Fig.  1).  This  progression  was  still 


16  UNIVERSITY    OF   CALIFORNIA — EXPERIMENT   STATION. 

quite  noticeable  in  July.  The  interesting  feature  of  this  progression  is 
the  fact  that  it  was  contrary  to  the  direction  of  the  wind,  which  blew 
daily  across  the  plot  in  the  direction  shown  by  the  arrow.  The  wind 
blew  from  right  to  left;  the  disease  progressed  from  left  to  right;  a  leaf 
parasite  would,  other  things  being  equal,  follow  the  direction  of  the  pre- 
vailing wind.  Furthermore,  the  vines  were,  in  at  least  seven  tenths  of 
the  cases,  more  diseased  to  windward,  notwithstanding  the  Red-leaf 
disease  progressed  against  the  wind.  Again,  the  vines  that  were  some- 
what weakened  by  their  proximity  to  the  eucalypti  (see  shaded  part  of 
map)  and  were  shaded  by  them  in  the  afternoon,  were  barely  touched 
by  the  Red-leaf  disease,  and  that  only  after  the  terrific  hot  weather  in 
September.*  The  leaves  of  these  vines  were  thinner  and  less  consistent 
than  those  of  the  vines  in  constant  sunlight.  They  were  decidedly 
wanting  in  vigor,  and  yet  remained  practically  untouched  by  the 
disease. 

It  seems  difficult  to  reconcile  the  above  facts  with  the  development 
of  a  leaf  parasite.  We  are  more  inclined  to  believe  that  the  Red-leaf 
disease  is  due  to  the  same  causes  as  the  Folletage  and  the  Rougeot, 
namely,  a  disturbance  of  the  equilibrium  between  the  absorption  of 
water  by  the  roots  and  its  transpiration  by  the  leaves. 

The  soil  in  which  the  vineyard  is  planted  is  a  clay  loam  underlaid, 
at  a  depth  of  from  three  to  four  feet,  by  an  impermeable  clay  subsoil, 
at  the  left  of  the  plot;  in  the  middle,  however,  the  soil  is  deeper  and 
the  subsoil  more  permeable;  toward  the  right  the  soil  becomes  deeper 
still  and  more  gravelly  as  one  goes  down.  At  the  end  of  July  there 
was  from  2  to  3  per  cent  of  free  moisture  in  the  soil,  which  is  enough, 
as  the  vines  showed,  to  support  a  good  growth  and  crop  of  fruit,  but 
which  might  easily  become  inadequate  to  supply  the  demands  of  the 
leaves  in  moments  of  great  transpiration  activity. 

Wind,  as  is  well  known,  activates  transpiration  considerably  and, 
under  such  conditions,  might  well  become  the  inciting  cause.  If  we 
take  into  consideration  that  the  vines  were  more  affected  with  the  Red- 
leaf  disease  to  windward,  and  that  the  disease  progressed,  in  the  early 
part  of  the  season  at  least,  from  that  part  of  the  plot  underlaid  by  the 
impermeable  clay  to  that  with  the  freer  subsoil,  we  have  two  facts 
which  bear  out  our  hypothesis  very  well. 

This  hypothesis,  however,  lias  against  it  the  results  shown  by  section  3,  which  was 
sprayed  with  the  iron  sulfate  and  the  Bordeaux  mixture.  In  this  section,  at  the  end  of 
the  season,  there  was  not  more  than  ten  per  cent  of  the  vines  diseased,  whereas  in 
the  other  sections  the  percentage  of  diseased  vines  was  almost  double.  From  the 
production  of  the  vines  in  the  different  sections,  we  are  unable  to  gather  any  evidence 
for  or  againsl  our  hypothesis.    (See  Pig.  3.) 


*This  hoi   weather  occurred   on   the  6th,  7th,  and  8th  of  September,  when   the  ther 
mometer  -\ow\  :it  90°  and  Hi.")0  !•".  in  the  shade. 


OBSERVATIONS    ON    SOME    VINE    DISEASES   IN    SONOMA    COUNTY. 


17 


In  regard  to  the  effect  of  soil  fertility  on  the  Red-leaf  disease,  some 
evidence  well  worthy  of  experimental  control  was  obtained.  In  Sep- 
tember, 1903,  in  a  cursory  examination  of  the  vineyard  in  which  the 
experiment  plot  is  situated,  it  was  noted  that  the  foliage  in  a  "  block  " 
of  old  Mission  vines  which  were  much  larger  and  at  least  ten  years  older 
than  those  in  the  experiment  plot,  showed  very  generally  the  discolora- 
tion of  the  Red-leaf  disease.  These  old  Missions  were  given  a  good  dress- 
ing of  stable  manure  during  the  winter  of  1903.  In  1904  they  were 
kept  more  or  less  under  constant  observation.  On  September  16th  of 
that  year  we  noted  that  the  old  Missions,  which  the  previous  year 
showed  the  foliar  characters  of  the  Red-leaf  disease  so  markedly,  were 
still  healthy. 


Legend 

Te5o..VMD  SPRflYED  TTITH  IROn  SUUWTE 

Te5o  •*B=ywes  anwEowrn  n»n  sUtmmx 

ilHDBDRDEflUX  MJXTUEt 

B  •.vma  3rwwni"wrm  Bordeaux  rsxnna 

WW  ETC.  ■  VI71E5  UPTRDnEB/UU)  UfT  K> 
WJJffSSS; 


Tfe&o^  W(  Te5o    W}      B 
+B 


W     W.     W      B      W.     B      W, 


Fig.  3.    Table  showing  the  average  production  (in  pounds)  of  the  vines,  both  sprayed 
and  unsprayed,  at  the  South  Sonoma  Experiment  Plot. 

From  these  observations  one  would  surmise  that  fertilizing,  with 
stable  manure  at  least,  would  have  a  certain  action  in  controlling  the 
Red-leaf  disease.  Jf,  moreover,  coupled  with  these  observations,  it 
were  found  that  the  soil  was  at  all  deficient  in  one  or  all  of  the  plant 
foods,  then  our  surmise  would  become  a  plausibility,  if  not  a  certainty. 
We  had,  therefore,  the  soil  (an  average  sample)  of  our  experiment  plot 
analyzed,  and  with  the  following  result :  The  soil  was  found  to  contain 
less  than  0.05  per  cent  of  phosphoric  acid,  which  is  quite  low  for  a 
productive  soil.  When  we  couple  with  this  deficiency  of  phosphoric 
acid  the  fact  that  the  grapevine  consumes  more  of  this  nutrient  than 
most  fruit  trees,  it  is  not  rash  to  assume  that  fertilization  will  greatly 
help  the  vines  to  at  least  withstand  the  Red-leaf  disease. 


18  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

THE  GRAPE-SHRIVEL. 

The  disease  that  we  have  denominated  the  Grape-shrivel  is  not  as 
yet,  at  least  so  far  as  known,  of  any  great  economic  importance;  but, 
owing  to  the  circumstances  under  which  it  occurs,  it  is  highly  probable 
that  it  exists  elsewhere  in  the  reconstructed  vineyards  of  California 
and  may,  therefore,  assume,  at  any  moment,  more  than  local  interest. 
The  fact  that  we  observed  the  Grape-shrivel  in  the  East  Sonoma 
experiment  plot,  where  it  took  the  place  of  the  Red-leaf  disease,  is  sug- 
gestive enough,  even  though  it  was  not  observed  at  either  of  the  other 
experiment  plots,  or  in  vineyards  visited. 

Description  of  the  Grape-Shrivel. — The  Grape-shrivel,  as  its  name 
implies,  is  characterized  by  the  shriveling  of  the  berries.  In  fact,  this 
shriveling  is  the  only  diagnostic  character  of  this  disease,  the  symptoms 
which  appear  in  the  leaves  being  easily  referable  to  drought,  or  imper- 
fect nutrition. 

The  Grape-shrivel  develops  quite  rapidly,  as  shown  by  the  fact  that 
while  no  symptoms  of  the  disease  were  observed  on  the  27th  of  June, 
yet  on  the  12th  of  July  many  vines  were  affected.  By  the  end  of  July 
practically  every  vine  in  the  experiment  plot  showed  the  characteristic 
shriveled  grapes  of  this  disease. 

The  distribution  of  the  Grape-shrivel  is  at  first  somewhat  irregu- 
lar, then  general.  The  grapes  on  weak  vines  (not  necessarily  dying 
vines)  and  strong  vines  are  equally  affected.  The  fruit  on  weak  shoots 
and  strong  shoots  is  affected  alike.  The  general  health  of  the  vine 
seems  to  bear  no  relation  whatever  to  the  distribution  and  intensity 
of  the  disease.  Vigorous,  weakly  and  dying  vines  (all  with  affected 
grapes)  commingle ;  there  are  not  the  usual  regular,  or  semi-regular, 
depressed  areas  of  vegetation  so  characteristic  of  parasitic  diseases. 

Effect  of  the  Disease  on  the  Grapes. — The  Grape-shrivel,  as  already 
mentioned,  is  characterized  by  its  effect  upon  the  fruit.  The  berries* 
lose  their  clear,  turgid  appearance  and  become  dull  and  flabby  (but 
never  blotched,  as  in  the  Red-leaf  disease),  irregularly  wrinkled  and, 
as  it  were,  thick-skinned;  as  the  drying  progresses  the  wrinkling 
becomes  more  pronounced  and  assumes  a  direction  more  nearly  parallel 
to  the  axis  of  the  berry  (Fig.  4).  When  completely  dry  the  berries  are 
uniformly  bluish,  in  some  cases,  where  exposed  to  the  sun,  washed 
with  red;  they  are  tightly  shrunken  around  the  seeds,  and  coriaceous. 
At  this  stage  the  pedicels  and  the  peduncle,  to  within  a  short  distance 
of  the  cane,  are  dried  and  discolored;  the  green  and  dried  portions  of 
the  peduncle  become  severed,  and  the  completely  desiccated  bunch  of 

*As  we  have  only  observed  the  Grape-shrivel  on  one  variety  of  white  grape  (the 
Bemillon)  the  description  of  ih<;  effect  of  the  disease  on  the  berries  can  only  apply 
integrally  to  varieties  of  the  grapevine  producing  while  fruit. 


OBSERVATIONS   ON   SOME   VINE   DISEASES   IN   SONOMA    COUNTY. 


19 


grapes  falls  to  the  ground.  Such  is  the  progression  of  the  disease  in 
the  grapes  while  they  are  still  green,  but,  when  they  begin  to  mature 
the  shrinkage  becomes  less  total  as  the  absolute  percentage  of  sugar 
increases  in  the  fruit. 

The  fruit  of  diseased  vines,  when  it  does  not  shrivel,  often  ripens 
prematurely.  This  prematurely  ripened  fruit  is  frequently  edible, 
though  sometimes  quite  distasteful. 

The  manner  in  which  the  malady  works  on  the  different  bunches  of 
the  same  cane  is  quite  characteristic.     The  lower  bunch  of  grapes  is  the 


Fig.  4.    Bunches  of  grapes  showing  progress  of  Grape-shrivel. 

first  to  show  signs  of  the  disease;  it  is  not  rare  for  one  to  find  the  lowest 
bunch  much  diseased,  and  the  upper  just  beginning  to  show  the  first 
signs.  We  have  even  found,  on  canes  bearing  three  bunches  of  grapes, 
the  first  bunch  completely  desiccated,  the  second  shriveled,  and  the 
third  absolutely  sound.  There  are  canes,  however,  in  which  the  differ- 
ences are  less  marked,  and  some  even  in  which  the  progression  of  the 
disease  is  reversed. 

Effect  of  the  Disease  on  the  Leaves. — The  disease  does  not  show  in  the 
foliage  at  first.  The  leaves  of  strong,  healthy  vines  and  strong,  healthy 
shoots  remain  turgid  and  green;  the  leaves  of  weaker  vines  and  weaker 


20  UiNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

shoots  may  be  somewhat  faded  and  yellow.  The  yellow  coloration  may 
be  total  or  partial,  and  the  leaves  irregularly  dry  in  those  parts  of  the 
parenchyma  longest  deprived  of  chlorophyll,  that  is  from  the  edges 
inward.     The  lower  leaves  are  more  affected  than  the  upper. 

Following  the  shriveling  of  the  grapes,  the  foliage  of  the  more  vigor- 
ous vines,  after  a  longer  or  shorter  time,  begins  to  show  the  same  char- 
acters that  the  leaves  of  the  weaker  vines  assume  at  an  earlier  period. 
These  characteristics  are  illustrated  in  the  accompanying  colored 
figures  on  Plate  I.  The  chlorophyll  becomes  resorbed  at  the  edge  of 
the  leaf  (Plate  I,  Fig.  7),  which  yellows;  this  resorption  may  continue 
until  the  whole  of  the  leaf  is  bright  yellow  (Plate  I,  Fig.  1). 
Following  this  stage,  which  is  not  infrequent  in  the  basal  leaves,  the 
leaf  either  dries  up  completely  and  at  once  (Plate  I,  Fig.  3),  or,  as  occurs 
more  often,  from  the  periphery  inward,  with  a  slight  rolling  of  the  edges 
(Plate  I,  Fig.  2).  In  other  cases,  however,  the  entire  blade  of  the  leaf 
does  not  become  so  regularly  yellow  and  then  dry.  Indeed,  one  fre- 
quently observes  the  yellowing  at  first  confined  to  the  apical  lobe  (Plate 
I,  Fig.  4),  and  then  gradually  progressing  toward  the  petiole  (Plate  I, 
Fig.  5),  the  wings  of  the  leaf  remaining  the  while  of  a  sub-healthy  green. 
The  chlorotic  tissue  gradually  dries,  sometimes  irregularly,  but  not 
infrequently  in  a  very  regular  manner  (Plate  I,  Fig.  6).  As  soon  as 
the  center  portion  of  the  leaf  has  dried,  the  wings  of  the  leaf  die.  Fig.  6 
represents  a  leaf,  the  center  of  which  became  chlorotic  and  then  dried 
up;  the  death  of  the  entire  leaf  then  followed. 

A  leaf  presenting  the  characters  of  that  illustrated  in  Fig.  8  is  more 
exceptional.  In  this  leaf  the  greater  part  of  the  leaf-blade  was  sud- 
denly killed  without  previous  yellowing  or  chlorophyll  resorption.  The 
dead  tissue,  it  will  be  observed,  has  a  shade  of  green  in  it,  whereas  in 
all  the  other  diseased  leaves  it  is  fawn-colored  or  brown.  If  the  reader 
will  imagine  the  dead  tissue  (Fig.  8)  colored  brown  instead  of  greenish- 
fawn,  he  will  have  the  representative  of  a  leaf  that  was  chlorotic  around 
the  edges  and  in  the  greater  part  of  the  blade.  This  chlorosis,  however, 
did  not  spread,  and  the  affected  tissue  rapidly  died  without  impairing 
the  functions  of  the  remaining  healthy  portion  of  the  leaf. 

Internal  Appearance  of  the  Shoots,  Spurs,  Arms,  and  Body  of  Vines. — 
The  spurs,  the  arms,  and  the  body  of  the  vine  show  no  outward  signs  of 
disease  at  all.  The  shoots  mature  sometimes  very  unevenly,  but  this 
characteristic  is  unimportant.  The  shoots,  spurs,  and  body  of  the  vine 
show,  however,  certain  internal  symptoms  which  should  be  noted. 

Cross  and  longitudinal  sections  of  the  shoots,  spurs,  arms,  and  body 
of  the  vine  show  discolorations  in  the  wood  and  pith.  In  the  shoots  a 
slight  discoloration  of  the  woody  tissue  next  the  pith  can  be  traced  with 
comparative  ease  at  least  as  far  as  the  last  bunch  of  grapes  showing- 
shriveling;  but  the  brown  discolorations  in  the  pith  are  not  so  constant: 


OBSERVATIONS   ON   SOME   VINE   DISEASES   IN   SONOMA   COUNTY.  21 

now  and  then  they  may  occur  just  above  and  below  the  diaphragms, 
and  without  regularity;  at  other  times  a  slight  discoloration  of  the  pith 
may  be  traced  from  the  base  of  the  shoot  up  several  nodes.  In  the 
spurs  the  woody  tissue  of  the  previous  year  is  brown  and  often,  more 
especially  near  the  edge,  zoned  with  darker  lines.  In  the  arms  we  have 
the  same  general  appearance  as  in  the  spurs,  with  this  difference  that, 
in  cross-section,  the  darker  areas  may  be  more  suffused.  In  the  trunk 
the  discolor ations  of  the  wood  are  less  pronounced  and,  in  longitudinal 
section,  appear  as  striations  which  become  less  numerous  as  one  nears 
the  stock  (the  diseased  vines  are  grafted  on  Lenoir),  which  they  rarely 
penetrate  to  any  extent;  or,  if  no  decay  or  dead  tissue  is  present,  the 
live  wood  may  be  suffused  with  a  faint  brown  tinge,  from  which  the 
striations  stand  out  less  boldly.  The  bodies  of  the  vines  have,  however, 
in  most  cases  suffered  more  extended  disorganization  than  just  described. 
One  finds,  whenever  large  limbs  have  been  at  one  time  removed,  decay 
and  dead  tissues  occupying  a  large  part  of  the  body  of  the  vine  and 
eating  gradually  down  toward  the  stock,  which  is  rarely  affected,  how- 
ever, to  any  serious  extent. 

The  roots  are  always  healthy,  even  in  sickly  vines. 

Generalities  regarding  the  Work  at  the  East  Sonoma  Experiment  Plot. — 
This  plot  was  established  in  a  vineyard  reconstituted  some  twenty  years 
ago.  Lenoir  was  the  grafting  stock  originally  used;  but  from  time  to 
time,  as  vacancies  occurred,  other  stocks — mostly  Rupestris  of  the  Fort 
Worth  type — were  used  to  fill  in  the  missing  places.  In  that  part  of 
the  vineyard  selected  for  the  experiment  plot  (the  only  really  diseased 
portion)  the  Lenoirs  are  carrying  Semillon  grafts. 

The  plot,  however,  is  not  free  from  admixture.  A  few  Zinfandels  are  scattered  here  and 
there  and  were  evidently  accidentally  introduced  when  refilling  the  vacancies.  When  the 
vineyard  was  reconstituted  the  grafting  was  well  done  and  the  grafts  were  not  allowed 
to  strike  root.  Furthermore,  there  was  never  any  great  disparity  of  growth  between 
the  stock  and  graft,  and  consequently  the  unions  are  smooth.  The  vines  were  pruned 
short  prior  to  1902,  and,  in  consequence,  had  never  produced  much  of  a  crop,  the 
Semillon  being  one  of  the  grapes  that  demands  long  pruning  to  produce  fully.  The 
vines,  however,  under,  this  regime,  were  moderately  healthy  and  sufficiently  vigorous. 
In  1902  the  system  of  pruning  was  changed  from  short  to  long.  Following  the  adop- 
tion of  the  long  pruning  the  vines  began  to  show  disease.  In  1903  they  were  already 
much  affected.  This  new  disease  was  then  supposed  to  he  the  Red-leaf  disease.  We 
now  know  that  it  was  the  Grape-shrivel. 

Acting  on  the  assumption  that  the  disease  in  this  vineyard  was  the 
Red-leaf,  arrangements  were  made  in  February,  1904,  to  carry  out  there 
the  same  spraying  experiments  as  at  the  other  two  plots.  The  East 
Sonoma  plot  was  divided  into  twelve  sections,  containing  four  rows  of 
vines  each.  Sections  1  and  7  were  sprayed  with  acid  iron  sulfate,  * 
sections  3  and  9  with  acid  iron  sulfate  and  Bordeaux  mixture;  sections 
2,  4,  6,  and  12  were  left  as  witnesses.     Sections  1,  3,  7,  and  9  were 

*For  the  method  of  preparing  this  fungicide,  see  page  12. 


22  UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION. 

sprayed  with  the  acid  iron  sulfate  on  the  28th  of  March,  just  as  the 
buds  were  beginning  to  swell.  Sections  3,  5,  9,  and  11  were  sprayed 
with  Bordeaux  mixture  (4  pounds  of  copper  sulfate,  4  pounds  of  lime, 
40  gallons  of  water)  on  the  6th  and  26th  of  May,  and  the  16th  of  June. 

The  growth  of  the  vines  on  the  sprayed  and  unsprayed  rows  was 
sporadic  and  uneven.  After  the  second  spraying  with  Bordeaux  mixture 
the  foliage  of  the  sprayed  vines  was  somewhat  greener  than  that  of  the 
witnesses.  By  the  16th  of  June,  the  date  of  the  third  spraying  with  the 
Bordeaux  mixture,  no  specific  signs  of  disease  had  shown  in  either  the 
witnesses  or  the  treated  vines,  other  than  such  as  might  be  referred  to 
known  causes.  The  appearance  of  the  plot  was  in  no  way  such  as  to 
create  a  fear  that  the  vines  would  collapse  and  fail  to  ripen  their  fruit. 
On  the  27th  of  June  the  general  appearance  of  the  vines  was  somewhat 
wan,  and  the  line  of  demarkation  between  the  sprayed  and  unsprayed 
vines  had  well-nigh  ceased  to  exist.  On  the  12th  of  July,  however, 
almost  every  vine  in  the  plot  showed  unmistakable  signs  of  suffering; 
the  foliage  was  pale,  and  many  clusters  of  grapes  had  already  shriveled, 
or  were  just  beginning  to  collapse;  there  was  no  longer  any  difference, 
between  the  witnesses  and  the  sprayed  vines.  In  fact,  so  general  were 
the  symptoms  of  disease  in  both  the  treated  and  untreated  vines  that 
any  further  attempt  to  check  it  with  Bordeaux  mixture  was  given  up  as 
useless.  By  the  end  of  July  practically  every  vine  in  the  experiment 
plot  was  affected  with  the  Grape-shrivel,  with  the  exception  of  the  Zin- 
fandels  and  the  non-grafted  Lenoirs. 

On  the  21st  of  July,  when  well-nigh  every  vine  in  the  plot  was  affected 
with  the  Grape-shrivel,  the  free  moisture  in  the  soil,  a  loam  underlaid 
at  the  depth  of  two  feet  with  a  gravelly  clay-subsoil,  varied  between 
nine  and  ten  per  cent. 

The  roots  of  the  stock  in  different  parts  of  the  plot  were  examined 
from  time  to  time  for  the  purpose  of  determining  their  resistance  to  the 
Phylloxera.  Nodosities  were  always  found  to  be  present  in  plenty,  both 
on  the  grafted  and  on  the  non-grafted  Lenoirs. 

At  the  end  of  July  one  per  cent  of  the  vines  in  the  experiment  plot 
were  dug  up,  split  open  and  examined.  The  result  of  this  examination 
is  given  on  page  20,  where  the  internal  appearance  of  the  shoots,  spurs, 
and  body  of  vines  affected  with  the  Grape-shrivel  is  described. 

In  the  beginning  of  August  a  critical  examination  was  made  of  the 
vines  in  the  plot,  for  the  purpose  of  determining  if  there  was  any  rela- 
tion between  the  vigor  of  the  vine  or  of  any  of  its  individual  shoots, 
and  the  Grape-shrivel.  The  only  fact  this  examination  clearly  revealed 
was  that  the  vines  had  been  given  too  liberal  a  pruning.  In  general, 
no  more  than  half  the  eyes  left  at  pruning  time  had  sprouted,  and 
sometimes  less. 

The  yield  of  the  experiment  plot  (one  acre)  was  about  700  pounds  of 


OBSERVATIONS   ON   SOME   VINE   DISEASES   IN   SONOMA    COUNTY.  23 

grapes.     The  Grape-shrivel  had  destroyed  the  four  or  five  tons  of  fruit 
that  the  showing  of  the  vines  in  June  would  have  led  one  to  expect. 

Cause  of  the  Grape-shrivel. — From  the  description  of  the  Grape-shrivel, 
and  the  manner  and  circumstances  under  Which  it  develops,  it  is  evident 
that  the  disease  is  a  peculiar  manifestation  of  imperfect  nutrition.  The 
yellowing  and  dying  of  the  leaves,  beginning  at  the  base  of  the  shoots, 
is  characteristic  of  vines  suffering  from  want  of  water.  Premature 
ripening  is  also  a  consequence  of  lack  of  water.  The  fact  that  the 
grapes  shrivel,  often  previously  to  the  discoloration  and  wilting  of  the 
foliage,  does  not  invalidate  this  contention;  for,  it  may  be  shown  that 
under  the  influence  of  drought,  or  a  paucity  of  free  water  in  the  soil,  the 
fruit  of  the  French  prune  will  shrivel  even  when  the  foliage  is  healthy 
and  luxuriant.  It  is,  therefore,  no  stretch  of  the  imagination  to  suppose 
that  the  same  phenomenon  happens  in  the  case  of  the  vine.  In  fact,  in 
several  cases  we  have  obtained  experimentally  the  characteristics  of  the 
Grape-shrivel  as  shown  in  the  grapes.  Our  experiments,  though  crude 
enough,  were  quite  instructive.  We  severed,  in  healthy  vines,  several 
long  canes  bearing  vigorous  shoots  carrying  well-developed  bunches  of 
grapes.  Almost  immediately  after  the  canes  were  severed  the  shoots 
began  to  wilt,  as  one  would  expect.  The  bunches  of  grapes,  however, 
generally  wilted  as  they  do  in  the  case  of  the  Grape-shrivel:  the  lower 
bunches  on  a  shoot  would  frequently  dry  out  faster  than  the  others. 
We  also  observed  that  the  pith  discolored  in  the  neighborhood  of  the 
diaphragms  first,  and  that  the  wood  tissue  became  discolored. 

The  discoloration  of  the  pith  in  the  shoots,  and  the  discolorations  in 
the  spurs,  arms,  and  trunk,  may  be  shown  to  occur  in  vines  under  very 
varied  and  divers  circumstances,  and  are,  therefore,  at  most  of  but 
secondary  importance. 

The  symptoms  of  the  Grape-shrivel,  then,  are  those  of  a  vine  suffering 
from  drought.     This  is  further  emphasized  by  the  following  facts: 

The  Lenoir,  the  stock  upon  which  the  Semillons  are  grafted,  is  not 
very  resistant  to  the  Phylloxera.  Its  rootlets  (which,  the  reader  will 
bear  in  mind,  are  the  active  agents  in  the  absorption  of  water)  were 
much  distorted  by  the  Phylloxera,  and  their  functions,  therefore,  inter- 
fered with.  This  fact  explains  how  it  is  that  a  vine  grafted  on  Lenoir 
(or  any  other  stock  sensitive  to  the  Phylloxera)  could  suffer  from  want 
of  water,  even  when  the  soil  contained  nine  or  ten  per  cent  of  free 
moisture.  But  it  may  be  asked,  why  does  the  non-grafted  Lenoir  not 
suffer  ?  This  question  is  easily  answered.  The  Lenoir  is  not  as  vigor- 
ous a  grower  nor  as  heavy  a  bearer  as  the  Semillon.  When  it  bears 
the  Semillon,  then,  or  any  other  vinifera  more  vigorous  than  itself,  its 
rootlets,  even  when  not  preyed  upon  by  the  Phylloxera,  are  unable  to 
take  up  and  transfer  to  the  graft  its  optimum  of  food;  and  the  bigger 


24  UNIVERSITY    OF   CALIFORNIA  — EXPERIMENT    STATION. 

and  finer  the  graft  the  greater  the  difficulty  the  Lenoir  has  in  supply- 
ing it  with  its  full  quota  of  nutriment. 

But  if  the  rootlets  of  the  Lenoir  are  much  damaged  by  the  Phylloxera, 
the  equilibrium  can  not  be  maintained  and  the  graft  will  show  signs  of 
distress.  Why,  then,  have  the  vines  at  the  East  Sonoma  experiment 
plot  lived  so  long  ?  The  answer  to  this  question  is,  that  the  vines  were 
formerly  short-pruned  and  were  unproductive,  but  that  since  1902  they 
have  been  long-pruned  and  made  to  produce  largely. 

In  the  first  case  the  equilibrium  between  the  stock  and  the  graft  was 
practically  maintained;  in  the  latter,  it  was  destroyed.  It  must  not  be 
forgotten,  however,  that  the  Phylloxera  is  in  a  measure  an  active  agent 
in  causing  the  Grape-shrivel,  and  that  the  severity  of  the  disease  during 
1903  and  1904  may  be  due  to  circumstances  favoring  the  development 
of  this  pest. 

In  combatting  the  Grape-shrivel  on  grafted  vines,  two  things  must  be 
taken  into  account:  First,  the  affinity  between  the  stock  and  the  graft; 
second,  the  resistance  of  the  stock  to  the  Phylloxera. 

The  affinity  (and  by  affinity  we  mean  all  the  necessaries  to  a  con- 
joint life)  between  stock  and  scion  is  to  be  maintained  in  equilibrium 
by  judicious  pruning,  supplemented  by  thorough  fertilization. 

The  resistance  of  the  stock  to  the  Phylloxera  will  be  indirectly 
heightened  by  fertilization;  but  if  then  found  to  be  insufficient,  it 
should  be  changed  for  a  more  resistant  one.  The  use  of  bisulfid 
of  carbon,  in  protecting  stocks  of  low  resistance  from  the  attacks  of 
Phylloxera,  is  not  at  present  an  economic  possibility. 


ROOT-ROT.* 

The  action  of  this  disease  in  its  main  characteristics  is  very  similar 
to  the  malady  known  among  the  French  as  the  Pourridie,  or  Blanc  des 
racines,  and  in  Germany,  according  to  Mr.  P.  Viala,f  by  the  name  of 
Weinstock-faule.  The  areas  of  depressed  vegetation  that  one  associates 
familiarly  with  the  action  of  the  Phylloxera,  are  characteristic  also  of 
the  Root-rot.  In  each  case  there  is  a  center  of  infection,  though,  when 
compared  with  the  Phylloxera,  the  Root-rot  spreads  more  slowly  and 
appears  circumscribed  or  local  in  its  action.  In  the  case  of  the  Root- 
rot  there  may  occur  many  small  centers  of  infection  in  close  proximity 
to  one  another  which  may  take  several  years  to  merge  into  one;  whereas, 
in  the  case  of  the  Phylloxera,  when  infection  is  so  general  that  several 
oenters  start  very  near  one  another,  they  rapidly  become  one. 

*  These  remarks  of  Mr.  Butler  on  the  Root-rot  are  of  very  great  importance  at  the 
present  time,  as  this  disease  is  doing  a  great  deal  of  damage  in  certain  parts  of  Santa 
Clara,  Sacramento,  and  San  Joaquin  valleys.  In  some  districts  the  Root-rot  is  far  more 
destructive  than  the  Phylloxera.    (E.  H.  T.) 

t  P.  Viala:  "  Lea  Maladies  de  la  Vigne,"  3ded.,  page  248. 


OBSERVATIONS    ON    SOME    VINE    DISEASES    IN    SONOMA    COUNTY.  25 

The  Root-rot  is  caused  by  a  fungus, — possibly  several;  fungi,- and  in 
its  usual  form  is  very  easily  recognized  upon  digging  up  any  vine 
within  an  infected  area.  The  roots  are  soft,  watery,  yellowish-brown 
in  the  entire  woody  cylinder,  and  more  or  less  permeated  with  whitish 
threads — the  mycelium  of  the  parasite — and  give  off  a  strong  nauseous 
fungous  odor.  As  the  lower  roots  are  destroyed,  and  the  mortification 
enters  the  body  of  the  vine  and  slowly  eats  its  way  in  the  trunk  to  the 
surface  of  the  soil,  and  even  above,  new  roots  are  sent  out  from  the  still 
healthy  encompassing  tissue;  these  roots,  in  turn,  become  riddled  with, 
and  succumb  to  the  attacks  of  the  fungus.  In  the  last  stages  of  the 
disease  (that  is,  when  the  vine  has  sent  out  a  few  feeble  canes  about  a 
foot  long)  one  invariably  finds  near  or  at  the  surface  of  the  soil,  a  very 
free  growth  of  young  tender  roots. 

Though  the  Root-rot  is  generally  of  the  form  just  described,  and  takes 
from  two  to  five  years  to  kill  the  vine,  it  may,  in  some  rare  cases  and  in 
young  vineyards,  spread  with  such  rapidity  that  it  kills  the  vines  in 
eighteen  months,  and  even  in  a  single  season.  Mr.  P.  Viala  observes: 
"The  vines  may  succumb  in  from  fifteen  to  eighteen  months,"  and  that 
he  "has  even  caused  their  death  in  six  months  by  placing  them  under 
the  most  favorable  conditions  for  the  development  of  the  Pourridie."  * 

The  author  observed,  during  the  summer  of  1904,  in  a  young  vine- 
yard, a  remarkably  intense  and  destructive  attack  of  Root-rot,  which,  in 
many  instances,  had  gained  an  entrance  into  the  vines  during  the  late 
spring  or  early  summer,  and  had  practically  ruined  the  greater  part  of 
them  by  October.  Many  there  were  that  would  not  "come  out"  in  the 
spring,  or,  if  they  did,  would  die  during  the  summer. 

The  growth  of  vines  affected  with  the  usual  form  of  Root-rot  resembles- 
that  of  vines  affected  with  the  Phylloxera.  Their  growth  gradually 
becomes  weaker  and  weaker,  and  the  vines  finally  die.  But  in  the  rapid 
form  of  this  disease  there  is  no  such  gradual  wasting  away.  The  foliage 
of  the  vines  becomes  chlorotic,  and,  if  the  weather  is  at  all  unfavorable, 
rapidly  sears  and  falls  off.  The  blade  of  the  leaf  not  infrequently  sep- 
arates from  the  petiole,  which  remains  a  while  longer  attached  to  the 
shoots.  The  maturity  of  the  shoots  is  impeded;  their  lignification  i& 
imperfect,  irregular,  and  at  times  resembles  that  which  has  come  to  be 
considered  typical  of  the  Anaheim  disease;  in  other  words,  strips  on 
elongate  spots  of  immature  tissue  may  be  found  in  the  midst  of  mature 
wood.  The  fruit  matures  imperfectly.  The  photograph  of  the  vine 
shown  in  Fig.  5  was  taken  early  in  October,  and  shows  the  general  appear- 
ance of  a  young  vine  affected  with  the  rapid  form  of  the  Root-rot.  The 
vine  was  evidently  not  affected  with  this  disease,  if  we  may  judge  from 
its  growth,  until  late  in  spring. 

The  appearance  of  the  diseased  vines  below  ground  is  necessarily 
different  from  that  of  those  affected  with  the  milder  form  of  the  Root- 
*P.  Viala:  "Monographic  du  Pourridie,"  Introduction. 


26 


UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION. 


rot.  Instead  of  the  entire  underground  portions  being  soft,  watery, 
and  decayed,  the  woody  cylinder  suffers  no  outward  disorganization, 
hut  is  more  or  less  discolored  according  as  it  is  examined  nearer  to  or 
farther  from  the  original  center  of  infection.     In  fact,  so  slight  is  the 


Fig.  5.    Young  vine  killed  by  Root-rot. 


decay  of  the  tissues  that  a  vine,  when  cursorily  examined  after  it  has 
been  dug  out,  shows  no  signs  of  a  specific  disease.  The  bark  on  the  stem 
is  tight  and  dry,  and  is  not  suggestive  ;  on  the  roots  it  is  often  streaked 
with   filmy  white,  but  even   this  is  not  characteristic  enough  to  hold 


OBSERVATIONS   ON   SOME   VINE   DISEASES   IN   SONOMA    COUNTY.  27 

one's  attention.  But  when  one  examines  a  diseased  vine  a  little  more 
closely  he  discovers  that  it  gives  off  the  nauseous  fungous  odor  so 
characteristic  of  the  Root-rot,  and  that  a  cross-section  through  the 
stem  or  roots  shows,  between  the  wood  and  the  bark,  a  dirty  white  sub- 
continuous  line,  which  is  not  very  distinct  and  is  easily  overlooked. 
If,  however,  a  piece  of  the  bark  is  cut  off,  there  will  appear  between  it 
and  the  woody  cylinder  a  white,  or  grayish  felt-like,  mass  of  interwoven 
threads — the  mycelium  of  the  Root-rot  fungus.  The  vine  shown  in 
Fig.  5  was  one  mass  of  this  fungous  growth  to  within  an  inch  or  so  of 
the  surface  of  the  soil. 

The  vineyard  in  which  the  exceptionally  severe  form  of  Root-rot  just 
described  was  observed  had  been  established  in  1902,  on  land  that  had 
been  cleared  during  the  year  1900.  The  piece  of  land  on  which  the 
vineyard  is  planted  lies  on  the  sunny  slope  of  a  fairly  steep  range  of 
hills.  This  slope  in  profile  might  be  likened  to  an  S  reversed  and  con- 
siderably drawn  out  lengthwise,  and  lying  at  an  angle  of  about  thirty 
degrees  with  the  horizontal.  The  soils  in  this  piece  of  land  are  both 
poor  and  good.  Beginning  at  the  bottom,  and  extending  up  the  slope 
some  one  hundred  feet,  we  find  a  very  shallow  sandy  soil,  inclined  to  be 
compact  and  hard,  and  underlaid,  at  a  depth  of  a  foot  or  more,  with  a 
clayey  subsoil.  This  soil  becomes  very  wet  in  winter.  On  the  remain- 
der of  the  slope  the  soil  is  friable,  inclined  to  red,  fertile,  and  with  the 
subsoil  considerably  below  the  surface.  In  this  soil  the  vines  may  be 
completely  dug  out  with  a  spade,  whereas  a  mattock,  and  a  good  one,  is 
needed  to  remove  the  vines  from  the  soil  at  the  bottom  of  the  hill.  The 
growth  of  oaks,  before  the  land  was  cleared,  was  meager  at  the  bottom 
of  the  slope,  on  the  refractory  soil,  but  quite  dense  everywhere  else.  A 
year  after  the  land  was  cleared  the  vines  were  planted.  They  were 
Carignanes  grafted  on  resistant  stocks.  On  the  light,  friable  soil  the 
Rupestris  St.  George  was  the  stock  employed;  whereas  on  the  refractory 
soil  at  the  bottom  of  the  hill,  Rupestris  of  the  Fort  Worth  type  appears 
to  have  been  exclusively  used.  The  former  were  more  vigorous  than 
the  latter. 

These  being  the  facts  one  would  naturally  expect  the  Root-rot  to 
develop  first  among  the  Fort  Worth  Rupestris,  and  spread  from  these 
to  the  Rupestris  St.  George.  This  would  certainly  have  been  more  in 
accord  with  the  general  behavior  of  Root-rot  fungi.  The  reverse  was 
true,  however;  the  Rupestris  St.  George  and  not  the  Fort  Worth 
Rupestris  were  the  vines  affected. 

But  with  the  Root-rots,  like  with  many  other  parasites  of  both  the 
vegetable  and  animal  kingdoms,  the  usual  areas  of  adaptability,  when 
one  or  more  conditions  are  particularly  favorable,  may  be  passed  over. 
In  fact,  it  is  well  known  that  in  the  case  of  the  Root-rot,  though 
usually  serious  only  in  wet  soils,  it  may  spread  in  comparatively  dry 


28  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT    STATION. 

soils  if  the  plants  growing  in  said  soils  happen  to  be  sensitive  to  the 
disease,  and  climatic  conditions — a  wet  winter,  for  instance — are 
favorable. 

In  the  case  of  the  rapid  form  of  the  Root-rot  affecting  the  young 
vineyard  above  mentioned,  we  know  that  the  land  was  full  of  decaying 
roots  and  other  debris  from  the  oaks  that  had  been  grubbed  out;  we 
also  know  that  Rupestris  St.  George  is  very  sensitive  to  this  disease, 
and,  furthermore,  that  the  latter  part  of  last  winter  was  wetter  than 
usual. 

The  intensive  and  rapid  growth  of  the  Root-rot  in  a  three-year-old 
vineyard  grafted  on  Rupestris  St.  George,  and  established  in  a  soil 
which,  from  its  situation  and  friability,  would  be  considered  unfavor- 
able to  the  development  of  the  parasite,  is  beyond  a  doubt  exceptional. 
However,  this  particular  case  has  been  dwelt  upon,  less  on  account  of 
its  economic  importance  than  for  the  fact  that  it  demonstrates  very 
conclusively  the  sensitiveness  of  the  Rupestris  St.  George  to  Root-rot,  a 
point  which  we  shall  have  occasion  to  dwell  upon  again. 

Vines  affected  with  the  rapid  form  of  the  Root-rot  can  not,  of  course, 
be  saved.  Vines  affected  with  the  usual  form  are,  when  treated  before 
the  disease  has  made  much  progress,  amenable  to  treatment.  The  pre- 
ventive treatment  here  recommended  applies  equally  well  to  both  forms 
of  Root-rot. 

The  remedial  or  preventive  measures  used  in  combatting  the  Root-rot? 
or  indeed  any  other  disease  attacking  the  subterranean  organs  of  plants, 
are,  at  best,  but  palliatives.  As  the  disease  is  more  general  in  soils  with 
an  impermeable  substratum  that  are  quite  retentive  and  miry  after 
heavy  rains,  adequate  drainage  is  and  will  always  remain  the  only 
valuable  preventive  and  curative  measure.  For  excessive  humidity  is 
the  exciting  cause  of  the  disease;  it  favors  fungous  development,  and  the 
tissues  of  the  roots  are  soft,  gorged  with  water,  and  in  no  condition  to 
resist  the  attacks  of  parasites.  An  author  (Mr.  P.  Viala*)  who  has 
studied  the  Pourridie  of  the  vine  and  fruit  trees  with  particular  care, 
says:  "One  must,  to  prevent  the  disease  from  spreading,  and  to  protect 
one's  self  against  it  in  new  plantations,  thoroughly  drain  the  soils  in  which 
it  exists,  and  also  those  that  are,  through  their  retentiveness,  favorable 
to  its  development."  "Drainage  is  an  excellent  preventive  measure," 
he  continues,  "and  what  is  more,  the  only  efficacious  one."  But  as 
drainage  is  not  always  economically  possible,  a  few  half  measures  that 
are  at  least  useful  may  be  mentioned,  even  if  they  have  not  the  virtue 
of  an  elixir. 

As  soon  as  the  disease  shows  in  the  vineyard,  all  badly  diseased  vines 
(that  is,  those  vines  whose  scant  growth  shows  that  their  main  root- 
system  is  seriously  attacked)  should  be  removed  and  the  vines  surround- 

*Loc.  cit.,  page  248. 


OBSERVATIONS    ON    SOME   VINE   DISEASES   IN    SONOMA    COUNTY.  21) 

ing  them  treated  with  a  three  per  cent  solution  of  blue  vitriol*  or  a 
seven  per  cent  solution  of  green  vitriol,  f  This  is  done  by  digging  with 
a  hoe  a  small  basin  around  the  trunk  of  the  vines  and  pouring  into  it  a 
gallon  or  so  of  either  solution,  the  quantity  being  determined  by  the 
nature  of  the  soil  and  the  supposed  extent  of  the  root-system.  If  for 
any  reason  it  is  inconvenient  to  treat  the  vines  with  either  of  the  vitriol 
solutions,  a  pound  of  either  the  bluestone  or  the  copperas  may  be  placed 
around  the  trunks  and  allowed  to  dissolve  in  the  winter  rains;  but  this 
method  will  not  be  as  effective.  Before  replanting  the  areas  destroyed 
by  the  rot,  the  holes  destined  to  receive  the  young  vines  should  be 
partly  rilled  with  either  blue  or  green  vitriol  solution,  and  then,  when 
the  fungicide  has  soaked  away,  planted.  In  soils  that  are  subject  to 
the  Root-rot,  rooted  vines  should  always  be  planted,  and  as  shallowly 
as  cultivation  will  permit.  Cuttings  should  never  be  used,  for  they  have 
to  be  planted  deeper  than  rooted  vines,  the  chances  of  infection, 
especially  on  the  cut  surface,  being  thereby  increased. 

Vineyards  that  have  once  been  infected  with  the  Root-rot  are,  unless 
drained,  always  subject  to  it;  therefore,  it  is  essential  that  those  parts 
that  have  been  destroyed  by  this  disease  should,  when  replanted,  be 
treated  every  two  or  three  years  by  one  of  the  methods  above  outlined. 

The  Root-rot  attacks  not  only  the  common  grapevine  (Vitisvinifera), 
but  probably  also  more  or  less  severely  the  different  resistant  stocks. 
The  Rupestris  St.  "George  is  very  sensitive  to  it;  but  according  to  Mr. 
Jallabert,J;  whose  demonstration  is  quite  convincing,  the  Riparia  X 
Rupestris  3306  is  almost  immune.  He  planted  the  latter  in  a  soil 
infected  with  the  Pourridie  and  which,  even  in  the  dog  days,  could  only 
be  worked  to  a  depth  of  six  inches.  "Somewhat  below  this  the  clay 
was  saturated,  and,  lower  down,  mud."§  In  such  a  soil  as  this,  and 
despite  the  Pourridie,  the  3306  flourished.  We  may  feel  confident,  then, 
that  wherever  the  Root-rot  is  bad  in  California,  the  Riparia  X  Rupes- 
tris 3306  will  more  than  hold  its  own. 

*J.  Dufour  in  "Chronique  Agricole  du  Canton  de  Vaud,"  quoted  by  G.  Foex, 
"  Cours  Complet  de  Viticulture,"  4th  ed.,  page  603. 

t  J.  Bonjour:  "  Manuel  Pratique  du  Vigneron,"  page  71. 

X  J.  Jallabert:  "  Resistance  du  Rupestris  du  Lot  et  du  Riparia  X  Rupestris  3306  au 
Pourridie,"  Revue  de  Viticulture,  tome  XI,  page  92. 

§  Loc.  cit.,  page  94  et  suiv. 


CALIFORNIA  PUBLICATIONS  AVAILABLE  FOR  DISTRIBUTION, 


REPORTS. 

1896.  Report   of    the    Viticultural    Work   during   the   seasons    1887-93,    with    data 

regarding  the  Vintages  of  1894-95. 

1897.  Resistant   Vines,   their    Selection,   Adaptation,   and   Grafting.      Appendix   to 

Viticultural  Report  for  1896. 

1898.  Partial  Report  of  Work  of  Agricultural  Experiment  Station  for  the  years 

1895-96  and  1896-97. 
1900.     Report  of  the  Agricultural  Experiment  Station  for  the  year  1897-98. 

1902.  Report  of  the  Agricultural  Experiment  Station  for  1898-1901. 

1903.  Report  of  the  Agricultural  Experiment  Station  for  1901-1903. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-1904. 

BULLETINS. 
Reprint.     Endurance  of  Drought  in  Soils  of  the  Arid  Region. 
No.  129.     Report  of  the  Condition  of  Olive  Culture  in  California. 

131.  The  Phylloxera  of  the  Vine. 

132.  Feeding  of  Farm  Animals. 

133.  Tolerance  of  Alkali   by   Various   Cultures. 
135.     The  Potato- Worm  in  California. 

137.  Pickling  Ripe  and  Green  Olives. 

138.  Citrus  Fruit  Culture. 

139.  Orange  and  Lemon  Rot. 

140.  Lands  of  the  Colorado  Delta  in  Salton  Basin,  and  Supplement. 

141.  Deciduous  Fruits  at  Paso  Robles. 

142.  Grasshoppers  in  California. 

143.  California   Peach-Tree   Borer. 

144.  The  Peach-Worm. 

145.  The  Red  Spider  of  Citrus  Trees. 

146.  New  Methods  of  Grafting  and  Budding  Vines. 

147.  Culture  Work  of  the  Substations. 

148.  Resistant  Vines  and  their  Hybrids. 

149.  California   Sugar  Industry. 

150.  The  Value  of  Oak  Leaves  for  Forage. 

151.  Arsenical  Insecticides. 

152.  Fumigation  Dosage. 

153.  Spraying  with  Distillates. 

154.  Sulfur  Sprays  for  Red  Spider. 

155.  Directions  for  Spraying  for  the  Codling-Moth. 

156.  Fowl   Cholera. 

157.  Commercial  Fertilizers. 

158.  California  Olive  Oil;  its  Manufacture. 

159.  Contribution  to  the  Study  of  Fermentation. 

160.  The  Hop  Aphis. 

161.  Tuberculosis   in   Fowls. 

162.  Commercial  Fertilizers. 

163.  Pear  Scab. 

164.  Poultry  Feeding  and  Proprietary  Foods. 

165.  Asparagus  and  Asparagus  Rust  in  California. 

166.  Spraying  for  Scale  Insects. 

167.  Manufacture  of  Dry  Wines  in  Hot  Countries. 

CIRCULARS. 

No.  1.     Texas  Fever.  No.  10.     Reading    Course     in     Economic 

2.  Blackleg.  Entomology. 

3.  Hog  Cholera.  11.     Fumigation   Practice. 

4.  Anthrax.  12.     Silk  Culture. 

5.  Contagious  Abortion  in  Cows.  13.     The  Culture  of  the  Sugar  Beet. 

6.  Methods  of  Physical  and  Chem-  14.     Practical    Suggestions   for   Cod- 

ical   Soil  Analysis.  ling-Moth      Control      in      the 

7.  Remedies  for  Insects.  Pajaro  Valley. 
9.     Asparagus  Rust. 

Copies  may  be  had  by  application  to  the  Director  of  the  Experiment 

Station,  Berkeley,  California. 


